ref(builder): remove python and jq from the builder script. replaced by small go apps.
fix(builder): cleanup binaries after `make build`
ref(builder): use `docker create` for build target
fix(builder): avoid issues with non-string release values
fix(builder): supply empty default process type

Heroku buildpacks are not required to send one. If none is provided,
it should be an empty list.
test(tests): supply envvar with spaces
ref(builder): move sshd_config to etc/
ref(builder): move builder to image/, add unit tests

This move refactors some parts of the builder to go, as well as
allowing the possibility of re-writing the entire component in Go
in the future.
fix(builder): switch exit codes to 1

No point in using 64 as there's no significance tied to the
number 64.
test(builder): recursively test all packages
style(builder): compress into one-liners
ref(builder): create Reader after error handling
style(builder): typo
fix(builder): revert to testing local package

`go test` doesn't like it if there's multiple main scripts in the same
directory. Since there are no other packages to test, `.` tests
everything.

From a platform-wide perspective this does seem odd, but it's only
because builder is not built with Go from the ground up, whereas the
logger, logspout and publisher are pure Go.
Merge pull request #2335 from bacongobbler/replace_bash_parts_with_go

ref(builder): remove python and jq from the builder script